Uno Platform is an open-source .NET development platform that lets developers build native mobile, web, desktop, and embedded applications from one C# and XAML codebase. It is intended for .NET developers who want to share application code across multiple operating systems and device types. The catalogue entries support development workflows for Uno Platform with skills, agents, commands, and instructions.
Borrowing it
Nothing to install: this file belongs to unoplatform/uno. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/unoplatform/uno/master/.claude/skills/devserver/SKILL.mdgit clone --depth 1 https://github.com/unoplatform/unoWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/unoplatform/uno/devserver)<a href="https://agentmods.dev/skills/unoplatform/uno/devserver"><img src="https://agentmods.dev/badge/skills/unoplatform/uno/devserver/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/unoplatform/uno/devserver"><img src="https://agentmods.dev/badge/skills/unoplatform/uno/devserver.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00079 | $0.02209 |
| Opus 5.5 | $0.00032 | $0.00884 |
| Sonnet 5.5 | $0.00016 | $0.00442 |
| Haiku 4.5 | $0.00008 | $0.00221 |
Grade A, and why
devserver scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.
DevServer (CLI / Host / MCP)
Maintain and extend the Uno DevServer: the CLI tool, the Host process, MCP proxy integration, and add-in discovery. The DevServer projects are independent of the UI framework and do not require crosstargeting_override.props.
1. Architecture — a 2-process chain
- CLI (
Uno.UI.DevServer.Cli) – entry point, user-facing commands, MCP STDIO proxy, start-lifecycle management. - Host (
Uno.UI.RemoteControl.Host) – ASP.NET Core server for Hot Reload, IDE channel, processors.
The CLI start command handles existing-server detection (AmbientRegistry), IDE channel rebinding, port allocation, and launches the Host in direct mode (no --command), so all arguments (including --ideChannel) reach the Host via IConfiguration regardless of Host binary version. Non-start commands (stop, list, cleanup) use the Host's controller mode (--command=<verb>). The CLI can also run in MCP mode (--mcp-app) as a Model Context Protocol proxy between AI agents and the running Host.
Packages
| NuGet Package | Contents |
|---|---|
Uno.DevServer |
CLI tool (installed via dotnet tool) |
Uno.WinUI.DevServer |
Host binaries, processors, BuildTransitive targets |
2. Source map
| Directory | Purpose |
|---|---|
src/Uno.UI.DevServer.Cli/ |
CLI tool: commands, helpers, MCP proxy |
src/Uno.UI.DevServer.Cli/Helpers/ |
Discovery, caching, process helpers |
src/Uno.UI.DevServer.Cli/Mcp/ |
MCP server, client proxy |
src/Uno.UI.RemoteControl.Host/ |
Host process: server, extensibility, IDE channel |
src/Uno.UI.RemoteControl.Host/Extensibility/ |
Add-in loading and discovery |
src/Uno.UI.RemoteControl.DevServer.Tests/ |
Unit and integration tests |
build/test-scripts/ |
PowerShell integration test harness |
build/nuget/Uno.WinUI.DevServer.nuspec |
NuGet package definition |
Key files: CliManager.cs (command router), UnoToolsLocator.cs (SDK/package discovery from global.json, NuGet cache, AmbientRegistry), TargetsAddInResolver.cs (fast add-in discovery via .targets XML), ManifestAddInResolver.cs (manifest-first discovery from devserver-addin.json), DotNetVersionCache.cs, McpStdioServer.cs, ProxyLifecycleManager.cs, McpUpstreamClient.cs, ToolListManager.cs, DevServerMonitor.cs (+ MonitorDecisions.cs, pure decision logic for testability), HealthService.cs/HealthReport.cs, DiscoveryIssueMapper.cs, ConnectionState.cs, SolutionFileFinder.cs; Host: RemoteControlServer.cs (WebSocket server, processors), AddIns.cs (discovery + assembly loading).
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 96 lines · 79 tokens per session scan A f96b40e9b707
devserver is a skill published in the GitHub repository unoplatform/uno (10,080 stars, last pushed today), licensed Apache-2.0. It adds 79 tokens to every session and 2,209 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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